Nielsen is the latest market research firm to state that smartphones have eclipsed standard mobile phones in the U.S. That’s just a confirmation of the findings of others, but other data the company released on Monday was far more interesting, delving into the variances supplied by race and gender.

The percentage of those in the U.S. with smartphones is now 50.4 percent, meaning more than half of U.S. mobile subscribers have moved from feature phones to devices like Android phones and the iPhone.

Ethnic minorities were more likely than whites to have a smartphone, according to the data. Asian-Americans were atop the heap, with more than 2/3 (67.3 percent) having a smartphone. Nearly 60 percent of Hispanic mobile subscribers carry a smartphone as do more than 50 percent of African-American mobile device owners. Meanwhile, only 44.7 percent of white mobile phone owners carry a smartphone.

Women outnumber men in the smartphone camp, as well. 50.9 percent of women own a smartphone, compared to 50.1 percent of men.

In Nielsen’s data, Android continues to be the most commonly used mobile platform, at 48.5 percent, while the iPhone is the most commonly used smartphone platform, at 32 percent of devices (you really didn’t think otherwise, now did you?).

RIM’s market share of the U.S. smartphone market has dropped to 11.6 percent. Microsoft, on the other hand, makes up 5.8 percent of smartphone users in the U.S, however, that number is deceiving. Of that number 4.1 percent consists of users of the archaic Windows Mobile platform, while Microsoft’s current generation Windows Phone devices make up only 1.7 percent, less than half the share of their obsolete predecessor.

Windows Phone is even less than the sad “other” category, which sits at 2.1 percent.

These results were for Q1 2012, and the hugely hyped Nokia Lumia 900 did not launch until April, or Q2. AT&T called the Lumia 900 a flagship device and it was considered Nokia’s re-launch in the U.S. (despite the earlier Lumia 710 on T-Mobile). It remains to be seen if Nokia’s devices can have an impact on Windows Phone uptake.